Electromagnetic flow rate control valve and high-pressure fuel supply pump using the same

Abstract

High-response and high-power electromagnetically driven flow rate control valve with flange portion forming an attracting surface on an anchor, a first peripheral surface portion having a diameter smaller than the flange portion, and a cylindrical non-magnetic area opposing an outer peripheral surface of the flange portion with a third clearance interposed therebetween are provided, and a first fluid trap portion communicating with the back pressure chamber via the third clearance is provided. When the diameter of the flange portion is enlarged in order to enlarge the cross-sectional area of the attracting surface, fuel that is displaced by the anchor is increased, but is partly absorbed in the first fluid trap portion, so that the fuel passing through the fuel channel does not increase in comparison with fuel before the diameter of the flange portion is enlarged. Accordingly, the cross-sectional area of the attracting surface may be enlarged.

The invention claimed is: 
     
       1. A plunger-type high-pressure fuel supply pump having a cylinder provided in a pump;
 a plunger slidably provided in the cylinder and configured to reciprocate in accordance with rotation of a cam; 
 a fluid compression chamber defined by the plunger and the cylinder; 
 an electromagnetic valve provided in a space defined between the compression chamber and a fluid intake channel; and 
 a discharge valve provided in a space defined between the compression chamber and a fluid discharge channel; 
 wherein the electromagnetic valve includes:
 an anchor movable in an axial direction together with a valve body; 
 a back pressure chamber configured to be increased and decreased in volume by an action of the anchor; 
 a fixed magnetic attracting surface opposing an attracting surface of the anchor with a first clearance interposed therebetween; 
 a cylindrical magnetic area portion opposing an outer peripheral surface of the anchor with a second clearance interposed therebetween, the second clearance defining a fuel channel and also forming a magnetic circuit in cooperation with the anchor; 
 a flange portion forming the attracting surface on the anchor; 
 a first peripheral surface portion smaller than the flange portion in diameter; 
 a cylindrical non-magnetic area portion having an outer surface with a constant diameter and opposing an outer peripheral surface of the flange portion with a third clearance interposed therebetween, the second clearance being provided on an outer periphery of the first peripheral surface portion; and 
 a first fluid trap portion communicating with the back pressure chamber by the third clearance; and 
 
 wherein the third clearance is larger than the second clearance in cross-sectional area. 
 
     
     
       2. The high-pressure fuel supply pump according to  claim 1 , wherein the first peripheral surface portion includes
 a second peripheral surface portion having a smaller diameter formed integrally or as a separate member; and 
 a second fluid trap portion communicating with the first fluid trap portion via the second clearance. 
 
     
     
       3. The high-pressure fuel supply pump according to  claim 1 , wherein the second clearance and the third clearance are formed on the outer peripheral surface of the anchor. 
     
     
       4. The high-pressure fuel supply pump according to  claim 1 , wherein the valve body or a rod receives an urging force in a valve-opening direction by a spring, and that when there is no power distribution to the electromagnetic valve, a valve-opening state is maintained. 
     
     
       5. The high-pressure fuel supply pump according to  claim 4 , wherein the spring is provided in the back pressure chamber. 
     
     
       6. The high-pressure fuel supply pump according to  claim 4 , wherein the valve body includes
 two members of a valve body portion and a rod portion; 
 a first spring configured to urge the rod portion in the valve-opening direction; and 
 a second spring configured to urge the valve body portion in a valve-closing direction; and 
 wherein an urging force of the first spring is larger than an urging force of the valve spring. 
 
     
     
       7. The high-pressure fuel supply pump according to  claim 1 , wherein the valve body or a rod receives the urging force in a valve-closing direction by a spring, and wherein when there is no power distribution to the electromagnetic valve, a valve-closing state is maintained. 
     
     
       8. The high-pressure fuel supply pump according to  claim 7 , wherein the valve body includes two members of a valve body portion and a rod portion, a first spring configured to urge the rod portion in the valve-closing direction, and a second spring configured to urge the valve body portion in the valve-closing direction. 
     
     
       9. An electromagnetic flow rate control valve comprising:
 an anchor having a flange portion formed with a magnetic attracting surface and a first peripheral surface portion smaller than the flange portion in diameter and configured to be movable in an axial direction together with a valve body or a rod; 
 a fixed core including
 a fixed side magnetic attracting surface portion opposing an attracting surface of the anchor with a first clearance interposed therebetween, 
 a cylindrical magnetic area portion opposing the first peripheral surface portion of the anchor with a second clearance interposed therebetween, 
 a cylindrical non-magnetic area portion having an outer surface with a constant diameter and opposing an outer peripheral portion of the flange portion of the anchor with a third clearance interposed therebetween and configured to define a magnetic channel in cooperation with the anchor; and 
 a fluid trap portion communicating with the first clearance via the third clearance; 
 
 wherein the third clearance is larger than the second clearance in cross-sectional area. 
 
     
     
       10. The electromagnetic flow rate control valve according to  claim 9 , wherein the first peripheral surface portion includes
 a second peripheral surface portion having a smaller diameter formed integrally or as a separate member; and 
 a second fluid trap portion communicating with the first fluid trap portion via the second clearance. 
 
     
     
       11. The electromagnetic flow rate control valve according to  claim 9 , wherein the second clearance and the third clearance are formed on the outer peripheral surface of the anchor. 
     
     
       12. The electromagnetic flow rate control valve according to  claim 9 , wherein the third clearance is larger than the second clearance in cross-sectional area. 
     
     
       13. The electromagnetic flow rate control valve according to  claim 9 , wherein the valve body or the rod receives an urging force in a valve-opening direction by a spring, and that when there is no power distribution to the electromagnetic flow rate control valve, a valve-opening state is maintained. 
     
     
       14. The electromagnetic flow rate control valve according to  claim 13 , further comprising:
 a back pressure chamber configured to be increased and decreased in volume by an action of the anchor, 
 wherein the spring is provided in the back pressure chamber. 
 
     
     
       15. The high-pressure fuel supply pump according to  claim 13 , wherein the valve body includes
 two members of a valve body portion and a rod portion; 
 a first spring configured to urge the rod portion in the valve-opening direction; and 
 a second spring configured to urge the valve body portion in a valve-closing direction; and 
 wherein an urging force of the first spring is larger than an urging force of the second spring. 
 
     
     
       16. The high-pressure fuel supply pump according to  claim 9 , wherein the valve body or the rod receives the urging force in a valve-closing direction by a spring; and wherein when there is no power distribution to the electromagnetic valve, a valve-closing state is maintained. 
     
     
       17. The high-pressure fuel supply pump according to  claim 16 , wherein the valve body includes two members of a valve body portion and a rod portion, a first spring configured to urge the rod portion in the valve-closing direction, and a second spring configured to urge the valve body portion in the valve-closing direction.